Atherosclerosis represents a buildup of cholesterol and calcium in an artery, resulting in “plaque” that progresses to block off the artery. This disease may affect any artery in the body and is often present in multiple locations. The most common locations for atherosclerosis are:
Advanced atherosclerosis in these areas can lead to heart attack, amputation or stroke. Less commonly atherosclerosis can affect arteries that supply the kidneys or the intestine, which may lead to dysfunction of those organs. Atherosclerosis of the arteries to the arms does occur but it is relatively rare.
Targets for LDL are:
Targets for triglycerides are:
Target for HDL is:
While you cannot reverse the aging process or choose your parents, there are a number of things that can be done to reduce the risk of progression of atherosclerosis. These include:
Since diet and exercise are measures that most people can do on their own and are not associated with complications, this should be the first step, along with smoking cessation. If you are starting an exercise regiment for the first time, consult your primary care practitioner before beginning.
PAD is a type of atherosclerosis that involves the blood vessels supplying circulation primarily to the legs (less likely in the arms). It is a common condition and studies have shown that PAD can be identified in 5% of individuals between 60-69 years of age and in 15% of individuals who are 70 years of age or older. PAD prevalence increases with age and is more common in individuals who smoke or have one of the risk factors described. PAD is increased in patients who have had heart attack or stroke or who have had any vascular surgery, including angioplasty.
Claudication: Claudication comes from the Latin word for “limp.” It is defined as pain, tiredness or weakness in the muscles of the calf, thigh or buttocks that occurs with exercise (walking), which is then relieved when you rest or stop the activity. Symptoms of claudication result from the muscles’ increased demands for oxygen during physical activity that cannot be met due to reduced blood flow from narrowed or blocked arteries. As a result of impaired circulation, leg muscles will tire or become painful (cramping or weakness). Symptoms of claudication are very repeatable and often occur after the same type of activity (walking, climbing stairs or a hill) and do not occur in the muscles of the foot. It can often be managed medically and, in most cases, there is a low risk of amputation. Pains in the leg that are not brought on by exercise but instead occur during rest or after prolonged standing or sitting are not generally related to vascular disease. There may be many other causes of leg pain (arthritis, back problems, neuropathy). Critical Limb Ischemia (CLI): When the degree of blockage from PAD becomes severe, pain may occur without exercise and manifests in the foot, especially the toes (not the calf, hip or thigh). This is known as critical limb ischemia (CLI), and as the name implies, is an urgent condition that requires prompt consultation with a surgeon, as there is significant risk of amputation (unlike claudication). In general, patients will experience a burning pain occurring most often at night, which can be relieved by sitting up, hanging your foot over the side of the bed or sometimes even by walking. With CLI, the foot may lose color when it is elevated or become deep red or purple when you stand or sit. Small areas of dead tissue (gangrene) may develop, usually on the toes or other pressure points on the foot. In most severe cases, sores or ulcers may develop on the foot from minor injury—either on the toes or at sites of pressure (sole of foot or heel). If you develop a sore on the foot, especially if it does not heal quickly, you should be checked immediately for PAD. Diabetic neuropathy (nerve pain) can sometimes be confused with CLI and the conditions can sometimes coexist. However unlike the pain of CLI, diabetic nerve pain usually occurs in both feet, is not made better by hanging your foot down and is not associated with changes in color of the foot.
Although most patients with PAD have no symptoms, it can be easily and painlessly diagnosed in the doctor’s office and is painless. The process involves measuring the systolic blood pressure at the ankle with a Doppler probe and a blood pressure cuff, then comparing that reading to the highest blood pressure taken in either arm. The ratio of these pressures is called the Ankle/Brachial Index (ABI) and a normal ABI is 0.9 to 1.2. Generally, the lower the ABI, the more severe the PAD. For example, when an ABI is performed and the result is generally less than 0.45, you may have critical limb ischemia (CLI), a severe form of PAD that may result in amputation if left untreated. You should discuss an ABI screening—which is more accurate than feeling for a pulse in the foot—with your physician after you reach the age of 55, or earlier if you smoke, have diabetes or high cholesterol. This can be done as part of your regular examination or in a vascular laboratory.
Specific management strategies for symptomatic PAD differ depending on the severity of the symptoms—whether you have claudication or CLI. Patients with PAD are likely to have coronary artery disease or carotid artery disease, even if they are asymptomatic. Since stroke and death are common in patients with PAD, it is important to look for evidence of these conditions in all patients with PAD.
It is important to remember that patients whose only PAD symptom is claudication are not in immediate danger of amputation. Only about 15-20% of patients whose only symptom is claudication will eventually progress to the point where amputation might be a concern. In fact, patients with claudication are more likely to have a heart attack than to have an amputation. Therefore the goals of treatment are symptom relief, identification of silent atherosclerosis in other areas (heart, carotid arteries), and general treatment of atherosclerosis to prevent worsening of the condition or problems of myocardial infarction or stroke. Management techniques include:
In the case of CLI, the circulation has deteriorated to the point that it must be improved rather than stabilized. The major goals in patients with CLI are to relieve pain, heal ulcers and prevent amputation. While medical management techniques are similar for claudication (see above), and smoking cessation is critical, medical management is usually not sufficient in patients with CLI. Pletal has no clear role in patients with CLI, so interventionis often required.
Patients who have failed in the medical management of claudication may be considered for intervention. Some patients are so incapacitated by their symptoms that they choose intervention as the initial treatment. This is acceptable as long as the patient realizes all interventions are associated with risk and that all of them are subject to failure at some future date. Patients may be treated by “endovascular” surgery (angioplasty with or without stents) or surgical bypass. The choice of intervention will be determined after discussion with the surgeon and will be based on the location and severity of the disease, the overall health of the patient and patient preference and expectations. Some things to consider prior to intervention for claudication include:
A general comparison between Angioplasty/Stent and Surgical Bypass is shown in the table below. In general, after any intervention, patients should begin an exercise program and take an aspirin and statin to reduce the risk of recurrent problems. Cilostazol should not be needed after a successful intervention.
|Comparison of Angioplasty/Stent and Surgical Bypass for Claudication|
|Preferred in:||Larger vessels||Smaller vessels (<4 mm)|
|Preferred in:||Shorter blockages||Longer Blockages (>20cm)|
|Hospital Stay:||Outpatient or Overnight||Inpatient (3-7 days)|
|Anesthesia:||Local with sedation||General or Spinal|
|Recovery at home:||One week or less||3-4 weeks|
|Durability:||About 50% at 2 years||60-75% at 5 years|
Since intervention is usually required for CLI, patients will need a study (ultrasound, angiogram) to determine the extent of the blockage and plan either angioplasty or surgical bypass. Furthermore, patients should be evaluated for coronary artery disease, which is present in almost all patients with CLI. When possible, any significant coronary disease should be controlled before CLI intervention. Patients with CLI are generally older and sicker than patients with claudication and their disease is more extensive. Consequently, advanced endovascular techniques may be required to achieve success in these circumstances. Recommendations on preferred treatment of patients with CLI are evolving and treatment decisions should be made after consultation with a vascular surgeon who is experienced in both open surgical bypass and advanced endovascular techniques. A large study comparing endovascular surgery and open surgical bypass suggests that endovascular gives equal results with less complication rates for the first two years, but after that, open surgery is superior. Therefore, decisions on appropriate therapy depend on many factors including the patient’s overall medical condition. Post Intervention Care—after intervention, patients should take aspirin, Clopidogrel or both. Clopidogrel is recommended for at least 6-8 weeks, after which aspirin alone is sufficient. Patients should be on a statin drug and should continue risk reduction, which includes no smoking and control of diabetes, cholesterol and high blood pressure. The most common problem after intervention (besides recurrence) is myocardial infarction and patients should follow up with their primary care physician or cardiologist to prevent this condition. After any intervention, patients should be seen regularly for life. Any intervention can fail, but if caught in time, the problem can be corrected. Most failures occur during the first two years after intervention. Therefore, it is recommended that patients see their surgeon after one month, and every 3-6 months thereafter for two years. If everything looks good at two years, annual follow up is sufficient. If symptoms recur at any time, you should go back to your surgeon.
Atherosclerosis of the carotid arteries is important because it is a major cause of stroke. There are about 750,000 new strokes per year in the United States and about 20% are associated with disease of the carotid arteries in the neck. Furthermore, about two-thirds of strokes occur without warning. While most strokes occur in patients without carotid artery disease, when a stroke does occur, it is important to know whether or not significant carotid disease is present. “Significant” carotid disease narrows the carotid artery more than 50%. The more severe the narrowing, the more concerning the disease.
Any adult patient who has a stroke or Transient Ischemic Attack (TIA or “ministroke”) should be checked for disease of the carotid arteries in the neck. However, most patients with carotid artery disease are asymptomatic.In these patients, carotid stenosis can be suspected when a noise, or bruit, in the neck is heard with a stethoscope during a physical examination. While there may be several causes for such a bruit, individuals over the age of 60, or with a history of stroke, myocardial infarction, coronary bypass or angioplasty PVD, and/or smoking are more likely to have carotid disease. Significant carotid stenosis is rare in the overall adult population (less than 2%), but is present in 20-30% of individuals with stroke or TIA and in 5-10% of patients with a bruit who are over 60, smokers or have a history of coronary or peripheral artery disease.
Carotid artery disease is easily checked by Carotid Duplex Ultrasound.This is a simple non-invasive study that can detect plaque in the carotid arteries and determine the degree of blockage. You should talk with your primary care physician about whether or not you meet the criteria for a carotid ultrasound. Remember, not all insurance will pay for carotid ultrasound in patients without symptoms. Like PAD, the major long-term risk of carotid disease is myocardial infarction and cardiac evaluation along with risk reduction is very important in overall management.
While there are many causes of stroke, carotid stenosis is thought to cause about 20-25% of strokes in adults. Patients who have a stroke and are found to have a carotid stenosis have about a 30% chance of experiencing a second stroke, most often during the first weeks to one month after the initial event. Therefore, adults who have a stroke should be checked for carotid stenosis. The importance of carotid disease in patients without symptoms of stroke is more controversial. Narrowing of the carotid arteries by more than 50% is present in 2-4% of individuals over the age of 65; however, most of these people will never have a stroke. About 60-70% of patients who have a stroke have no warning signs, and therefore, the only suggestion that they have carotid disease may be a bruit in the neck or finding narrowing with a Carotid Duplex Ultrasound. When carotid artery stenosis is found in an asymptomatic individual, the overall risk of stroke and death is increased. The risk of stroke increases with the degree of stenosis.
There is a common agreement that the general screening of all individuals for carotid disease is not necessary. However, there are certain circumstances where the likelihood of carotid disease is increased and screening may be considered. Patients over 60 years of age, who have more than one of these factors in their history, should consider screening studies. These include:
The benefit of surgery depends on the experience of the surgeon performing the operation and the overall health of the patient. In general, a surgeon performing Carotid Endarterectomy should have a complication rate (stroke plus death) of less than 6% in patients with symptoms and less than 3% in patients without symptoms. Experienced surgeons often have complication rates significantly less than that. It is important to know the surgeons results before considering surgery.
Carotid Endarterectomy (CEA): This is the standard treatment for carotid artery stenosis and is a procedure has been perfected over more than 50 years. It involves a 4-6 inches long incision in the neck to expose and clean out the diseased carotid artery. The procedure can be done under general anesthesia or regional (block) anesthesia depending on surgeon and patient preference. A hospitalization of 24-48 hours is routine. Post-operative pain is minimal and patients can return to normal activities in about a week. Experienced surgeons can perform CEA with complication rates of 3-4% in symptomatic patients and 1-2% in asymptomatic patients. Carotid Artery Stenting (CAS): This procedure has been used to treat carotid stenosis for more than 15 years. It was initially used to treat patients who were felt to be at increased risk from carotid endarterectomy. Like other endovascular surgery, CAS is performed under local anesthesia through a puncture in the groin. Patients usually have a 24-hour stay in hospital and are back to full activity within 48-72 hours. Complication rates for CAS are higher than those after CEA—6-8% for symptomatic patients and 3-4% for asymptomatic patients. Complications after CAS are also higher in patients over the age of 70 and in those with neurological symptoms. Because of this, CAS is only recommended in patients with symptoms of stroke or TIA when CEA is felt to be dangerous, and is not recommended for asymptomatic patients. Currently Medicare and most insurance companies will not pay for CAS in patients who are asymptomatic unless they are in a clinical trial. Comparison of CAS and CEA based on many clinical trials is presented in the table below. It is important to discuss specific complication rates, including stroke, death, myocardial infarction and local site complications with the operator performing the procedure.
|Comparison of Carotid Endarterectomy and Carotid Artery Stenting|
|Carotid Stenting||Carotid Endarterectomy|
|Anesthesia:||Local||General or Local Block|
|Hospital Stay:||24 hours||24 – 48 hours|
|Return to Full Activity:||2-3 days||7-10 days|
|Complication Rate (Stroke/Death):||6-8% for symptomatic patients 3-6% for asymptomatic patients||3-4% for symptomatic patients 1-2% for asymptomatic patients|
|Patients with Stroke or TIA:||When Carotid Endarterectomy is “high risk”||All other patients|
|Asymptomatic Patients:||Currently not recommended outside of clinical trials||Good surgical risk, life expectancy 3-5 years minimum|
After intervention, patients should be maintained on aspirin or Plavix (both if CAS is performed) and a statin. Plavix may be stopped in 2-3 months as long as aspirin is maintained. General risk factor reduction including smoking cessation is important. A postoperative ultrasound is usually done within the first month to check the results of intervention. Recurrence after either CAS or CEA is less than 10%, so ultrasound can be done at six months, 12 months and two years. If there is no evidence of recurrent disease at that time and the other carotid is normal, no further follow up is required. If disease is present in the other carotid, or recurrent disease occurs in the original artery, further follow up may be required.
An aneurysm is a bulging or ballooning of a blood vessel that is more than 150% of vessel’s normal size. This occurs because of damage to the vessel wall. The diameter of the artery is bigger in an aneurysm while it is smaller in atherosclerosis. The most common artery to develop an aneurysm is the aorta, followed by the iliac artery, femoral artery and popliteal artery. Aneurysms of ot